U.S. Pat. No. 4,666,530 (to Houser) discloses an apparatus for extracting dirt from ducting such as the duct work used in ventilation systems. A power unit is used to drive an auger or cleaning implement which is passed through the ventilation duct work to scour the inside surface of the duct work by means of flexible strands which dislodge the dirt. The disclosed apparatus uses a standard rotary drive cable connected to the power unit at one end and to an auger at the other end to cause the auger to rotate. The auger tends to be self-centering, but a distinct disadvantage of the apparatus disclosed by Houser and similar duct cleaning systems is that the rotary drive cable used in such systems makes the system very heavy and, therefore, limits the extent of travel into a continuous duct system.
U.S. Pat. Nos. 574,422 (to Hildreth), 754,955 (to Lemke), 1,584,740 (to Denny), 2,155,205 (to Rodgers) and 2,162,677 (to Reynolds) disclose fluid driven motors for use in flu or duct cleaning. The Denny and Rodgers patents disclosed air driven motors for driving a cleaning brush in a flu or a duct. While the Lemke patent discloses that a supply pipe may be attached to a casing of a rotary motor, none of this group of patents teaches a substantially rigid, yet lightweight conduit that serves as a handle for maneuvering a cleaning head.
Another cleaning apparatus is disclosed in U.S. Pat. No. 4,027,349 (to Clavin). The Clavin apparatus is adapted to travel along the interior of pipes and includes a pneumatic motor to drive a plurality of rotating brushes. The device disclosed by Clavin is not suitable for use in HVAC duct work, lined or unlined.
There are some problems which remain unaddressed by known cleaning devices. One such problem is how to enable easy, convenient cleaning of long, substantially continuous ducts by a single operator who can operate the cleaning apparatus with a high degree of safety. A cleaning apparatus should be able to be moved easily a substantial distance into a continuous duct, occupy a minimum amount of set-up time, and be adaptable to a wide variety of ducts including lined ducts.
Another problem is that many available cleaning devices, including devices such as the apparatus disclosed by Hauser, include standard rotary drive cables. Such cables, or liquid drive systems, make a cleaning device heavy, particularly as the distance from the working end to the operator increases. This limits the distance that such systems can be extended into a duct, requiring more expensive duct work with more access openings for cleaning. Another problem with drive cable systems is that the torque tends to wear or break the cable and the cable housing, particularly any joints therein, possibly injuring the operator.
Known duct, flu or pipe cleaning devices, including those devices disclosed in the above-noted patents, represent advances in the art. However, such equipment does not produce an optimally safe, effective cleaning system that can be tailored to onsite factors such as the length, diameter and type of the duct work to be cleaned. Therefore, an easily portable, safe duct cleaning apparatus for cleaning duct work as efficiently and safely as possible would be a decided improvement over known devices.